NAME

       "Tickit::Widget::ScrollBox::Extent" - represents the range of scrolling extent

DESCRIPTION

       This small utility object stores the effective scrolling range for a
       Tickit::Widget::ScrollBox. They are not constructed directly, but instead returned by the
       "hextent" and "vextent" methods of the associated ScrollBox.

ACCESSORS

   viewport
          $viewport = $extent->viewport

       Returns the size of the viewable portion of the scrollable area (the "viewport").

   total
          $total = $extent->total

       Returns the total size of the scrollable area; which is always at least the size of the
       viewport.

   set_total
          $extent->set_total( $total )

       Sets the total size of the scrollable area. This method should only be used by the child
       widget, when it is performing smart scrolling.

   limit
          $limit = $extent->limit

       Returns the limit of the offset; the largest value the start offset may be.  This is
       simply "$total - $viewport", with a limit applied so that it returns zero rather than a
       negative value, in the case that the viewport is larger than the total.

   start
          $start = $extent->start

       Returns the start position offset of the viewport within the total area. This is always at
       least zero, and no greater than the limit.

METHODS

   scroll
          $extent->scroll( $delta )

       Requests to move the start by the amount given. This will be clipped if it moves outside
       the allowed range.

   scroll_to
          $extent->scroll_to( $new_start )

       Requests to move the start to that given. This will be clipped if it is outside the
       allowed range.

   scrollbar_geom
          ( $bar_top, $mark_top, $mark_bottom, $bar_bottom ) = $extent->scrollbar_geom( $top, $length )

       Calculates the start and end positions of a scrollbar and the mark within it to represent
       the position of the extent. Returns four integer indexes within $length.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>